Grave digger



Dec. 29, 1970 I w L 3,550,294

GRAVE BIGGER Filed Feb. 28, 1968 I 4 Sheets-Sheet 1 INV NTOR ATTORNEYS MAURICE ELL I 9 M. I. FEWELL 3,550,294

GRAVE DIGGER Filed Feb. 28, 196B 4 Sheets-Sheet 2 Fig. 5

244 INVENTOR MAURICE I. FEWELL BY W004 am/,4

ATTORNEYS M. I. FEWELL GRAVE DIGGER Dec. 29. 1970 4 Sheets-Sheet 3 Filed Feb. 28, 1968 INVENTOR MAURICE I. FEWELL ATTORNEYS Dec. 29. 1970 M. I. FEWELL 3,550,294

GRAVE bmssa Filed Feb. 28. 1968 4 Sheets-Sheet MAURICE I. FEWELL Fig. INVENTORS ATTORNEYS United States Patent US. Cl. 37-191 10 Claims ABSTRACT OF THE DISCLOSURE An excavating apparatus comprising a boom-type digger supported for pivotal movement about one of its ends, for generally vertical reciprocation and for generally horizontal reciprocation in a direction generally perpendicular. to its pivot axis. The boom-type digger delivers earth to an anger which conveys the earth away from the apparatus. The apparatus is movably supported by independently driven wheels. The digger includes endless chains which carry teeth formed from metal strips to have main body portions, curved portions at each end of each main body and an extension portion connected to each curved portion. Each curved portion of a tooth is formed about an axis which defines an acute angle with the run of the chain to which the tooth is connected so that the extension portions of the tooth extend forwardly of its body portion in the direction of movement of the tooth.

It is a primary object of my invention to provide an excavating apparatus which is particularly suitable for digging graves and which is characterized by its compactness and maneuverability.

My apparatus comprises a boom-type digger having teeth carried by endless chains and is compact because its boom is supported for pivotal movement about a horizontal axis at one of its ends, the one end of the digger being supported for both vertical and horizontal reciprocation. The digger can be pivoted from a generally horizontally extending position to a generally vertically extending position.

Since a grave digging apparatus must be extremely manueuverable, I have provided a pair of independently driven wheels for supporting the digger, the wheels being mounted on brackets which are mounted for reciprocation on the main supporting frame of the digger. At a grave site, the wheels can be easily removed and the main frame supported on leveling arms which are preferably hydraulically actuated.

Another object of my invention is to provide such an apparatus which is arranged so that the earth removed from the grave can be collected without spillage about its perimeterv In connection with this object, I have provided an anger arranged to convey the earth away from the apparatus.

Still another object of my invention is to provide such an excavating apparatus comprising teeth which will cut into any type of soil and which can be easily cleaned during the digging operation. My preferred tooth structure will be described in greater detail hereinafter.

Other objects and features of the present invention will become apparent as this description progresses.

In the drawings:

FIG. 1 is a perspective view, partially cut away, of a preferred embodiment of my excavating apparatus;

FIG. 2 is a sectional plan view, also partially cut away, showing the main supporting frame of the apparatus;

FIG. 3 is an enlarged, fragmentary, sectional view taken from FIG. 2 generally along the line 3-3;

FIG. 4 is an enlarged, fragmentary, sectional view taken from FIG. 2 generally along the line 44;

FIG. 5 is an enlarged, fragmentary, elevation view of 3,550,294 Patented Dec. 29, 1970 the apparatus showing particularly the manner in which the digger is supported for pivotal movement about a horizontal axis;

FIG. 6 is a plan view of the digger;

FIG. 7 is a perspective view of one type of tooth used on the digger;

FIG. 8 is a perspective view of another type of tooth usedon the digger;

FIG. 9 is a fragmentary, sectional view, slightly enlarged, taken from FIG. 6 generally along the line 9-9 and showing a means for cleaning the teeth of the digger;

FIG. 10 is a fragmentary, sectional view taken from FIG. 9 generally along the line 10-10;

FIG. 11 is a somewhat diagrammatic view of the apparatus showing the manner in which the excavation of a grave is started;

FIG. 12 is another such diagrammatic view showing a further step in the excavation of the grave;

FIG. 13 is still another diagrammatic view showing the final step in the excavation of the grave; and

FIG. 14 is a schematic view of a hydraulic control system for controlling the operation of my excavating apparatus.

Referring now to the drawings, and particularly to FIG. 1, it will be seen that my apparatus 10 comprises a main horizontal support frame 12, a vertical frame 14, a digger 16 pivotally supported at one end on a support 18, the support 18 being mounted for vertical reciprocation on the vertical frame 14. The vertical frame 14 is mounted for reciprocation in a direction perpendicular to the pivot axis of the digger 16 on the frame 12. A leveling arm 20, 22, 24, 26 is disposed at each of the four corners of the frame 12, each leveling arm being pivotally connected to the frame 12 by means of a pin 28, A shoe 30 is pivotally connected to the distal end of each arm by means of a pivot pin 32 which is generally parallel to the pivot pin 28 at the other end of the arm.

A rigid, vertical column 34 is disposed at the rear end 36 of the frame 12 and another rigid, vertical column 38 is disposed at the forward end 40 of the frame 12. A fluid motor 42, 44, 46, 48 is operatively connected to each arm 20, 22, 24, 26 and arranged to pivot the arm downwardly so that its shoe 30 will engage the ground to supportand level the frame 12. The fluid motor 42 is connected between the column 34 and the arm 20, the fluid motor 44 is connected between the column 38 and the arm 22, the fluid motor 46 is connected between the column '38 and the arm 24 and the fluid motor 48 is connected between the column 34 and the arm 26. In the illustrative embodiment, each fluid motor 42, 44, 46, 48 comprises a hydraulic cylinder 50 pivotally connected to its associated column 34, 38 and a piston rod pivotally connected to its associated arm 20, 22, 24, 26 as indicated at 52.

In position over a grave site. the frame 12 can be supported entirely by the leveling arms 20, 22, 24, 26. In order to transport the apparatus 10 to a grave site, I have provided a pair of independently driven drive wheels 54 and 56 and a caster 58, each drive wheel 54, 56 being disposed at a side of the frame 12 (FIG. 2) and the caster 58 being disposed in the center of the forward end 40 of the frame 12. The manner in which the wheels 54 and 56 and the caster 58 are mounted to support the frame 12 will be discussed further along in this description.

The frame 12 comprises a pair of parallel, spaced apart tracks 60 and 62 (clearly seen in FIG. 2) which, in the illustrative embodiment, are steel I beams having a cross section such as that shown in FIG. 4. Thus, as seen in FIG. 2, the frame 12 is a rectangular frame, the longest sides of which are defined by the tracks 60, 62. A bracket 64, 66 is arranged for longitudinal reciprocation on each of the tracks 60, 62. In the illustrative embodiment, each bracket 64, 66 is mounted for reciprocation on the upper flange of the beam 60, 62 (FIG. 4) and antifriction means 68 are arranged to support the bracket on the track. A fluid motor 70, 72 (clearly seen in FIG. 2) is operatively connected to each bracket 64, 66 and' arranged to reciprocate the bracket on its track 60, 62. In the illustrative embodiment, each fluid motor 70, 72 comprises a hydraulic cylinder 74 connected to its track' 60, 62 as indicated at 76 and a piston rod 78 connected to its bracket 64, 66 as indicated at 80.

The vertical support frame 14 comprises a pair of parallel, spaced apart tracks 82 and 84 which, in the illustrative embodiment, are also steel beams having the cross section shown in FIG. 2. The track 82 is welded or otherwise securely fastened to the bracket 64 and the track 84 is welded or otherwise securely fastened to the bracket 66. Thus, the tracks 82, 84 reciprocate with the brackets 64, 66. A cross beam 86 is welded or otherwise securely fastened between the tracks 82, 84 as clearly seen in FIG. 1 to hold the tracks in their parallel, spaced apart relationship.

An inner and outer wheel support bracket 88, 90 is welded or otherwise securely fastened to each bracket 64, 66 so that the wheels 54, 56 can be selectively mounted either between the tracks 60, 62 or outside of the tracks 60, 62. Specifically, in the illustrative embodiment as best seen in FIG. 4, each wheel, 54, 56 carries a spur gear 92 which is mounted concentric with the axis of the wheel by means such as the illustrated screws 94 and the spur gear 92 and wheel are journal mounted on a hub 96 which extends outwardly from a member 98. A hydraulic motor 100 is mounted on an extension portion 102 of the member 98 so that its output shaft 104 extends generally parallel to the hub 96. A pinion 106 mounted on the output shaft 104 for rotation therewith is engaged with the spur gear 92 so that, when the motor 100 is energized, the wheel 54, 56 is driven relative to its support member 98.

Each member 98 is provided with an enlarged portion 108 which can be releasably fastened either to an inner support bracket 88 or to an outer support bracket 90. Specifically, each bracket 88, 90 is provided with a socket portion 110 for receiving the lower end of the portion 108 and an outwardly extending upper portion 112 having a hole 114 formed therein for receiving a pin 116 which engages the upper portion of the member 108 to hold the member in the bracket 88, 90. It will be apparent that, when the pin 116 is pulled in the direction of the arrow 118, the entire wheel assembly can be pivoted in the direction of the arrow 120 and thereby disconnected from the bracket 88.

From the above description, it will be clear that the wheels 54, 56 can be mounted either on the inside or on the outside of the frame 12 and that the brackets 88, 90 on which the wheels are mounted can be reciprocated along the track 60, 62 of the frame 12. This versatile mounting capability provides for great maneuverability of the apparatus 10. For instance, the wheels 54 can be placed on the inside of the frame 12 so that the apparatus can be moved between closely spaced tombstones, shrubs and the like. Further, the capability of moving the brackets 88, 90 longitudinally along the tracks 60, 62 greatly enhances the cornering or turning capability of the apparatus 10. That is, in order to make a very sharp turn, the wheels 54, 56 can be moved closer to the caster 58. Of course, the wheels 54, 56 must be removed from their positions inside the frame 12 before excavation of a grave can be started.

The hydraulic motor 100 for each wheel 54, 56 is reversible and the control valves for the motors, indicated generally by the reference numeral 122, are disposed at the top of the column 34 at the rear 36 of the frame 12. I have provided a seat 124 which is releasably connceted to the rear end 36 of the frame 12 as indicated at 126. A person sitting in the seat 124 can operate the valves 122 to steer the apparatus 10. l have found that, because each 4 wheel 54, 56 is independently driven and because the positions of the wheels relative to the frame 12 can be adjusted, the maneuverability of my apparatus 10 is greatly increased.

Further to enhance the maneuverability of my apparatus 10, I have provided means for removably fastening the caster 58 to the front end 40 of the frame 12 so that the caster can be mounted selectively on the outside or the inside of the frame. In the illustrative embodiment, the caster 58 is mounted on a member 128 which is arranged to be releasably clamped to the lower flange of the beam defining the front end 40 of the frame 12. Specifically, referring to FIG. 3, it will be seen that the member 128 is provided with a deep groove 130 for receiving one side of a flange 132 and that a toe clamp 134 is mounted on the member 128 and arranged to engage the other side of the flange 132, thereby releasably to fasten the member 128 to the flange 132. The toe clamp 134 secured to the member 128 by means of the bolt 136 and nut 138. Of course, the caster 58 must be moved from its position inside the frame 12 before excavation of the grave can begin.

The support 18 is mounted for vertical recprocation on the tracks 82, 84 of the vertical frame 14. In the illustrative embodiment, the support 18 comprises a slider 140, 142 mounted on each track 82, 84 for reciprocation therealong and-a framework 144, 146 welded or otherwise securely fastened to each slider 140, 142 as shown in FIGS. 1 and 5. The frameworks 144, 146, are tied together by a cross bar 148 welded or otherwise securely fastened thereto. fluid motors 150, 152 are provided for reciprocating the support 18 on the tracks 82, 84. In the illustrative embodiment, each fluid motor 150, 152 comprises a hydraulic cylinder 154 connected to its track 82, 84 as indicated at 155 and a piston rod 156 connected to its slider 140, 142 as indicated at 157.

An axle 158 is journal mounted between the distal ends of the frameworks 144, 146 as shown in FIG. 1 and 5, the axis of the axle 158 coinciding with the aforementioned pivot axis of the digger 16. Specifically, in the illustrative embodiment, a bearing block 160 is mounted on the distal end of each framework 144, 146 and the ends of the axle 158 are supported in these bearing blocks. A sprocket 162 is mounted on the axle 158 and keyed to the axle for rotation therewith. A driving means 164 is mounted on the support 18 and is drivingly connected to the sproket 162. The driving means 164 may be a gasoline engine or some other suitable means for driving a shaft. In FIGS. 1 and 5, I have shown the driving means 164 comprising an output shaft 166 which is drivingly connected to the sprocket 162 by means of a chain 168. Also, I have shown a conventional hydraulic pump 170 drivingly connected to the shaft 166 by means of a V-belt 172. The pump 170, which will be discussed in greater detail in conjunction with FIG. 14, is connected to the various hydraulic cylinders comprising my apparatus 10.

The illustrative digger 16 comprises a boom assembly 174 comprising three boom arms 176, 178, (FIG. 6) the proximal ends of which are pivotally mounted on the axle 158 as indicated by the reference numeral 182. The boom arms 176, 178 and 180 are secured together by cross members 184 and 186 and end members 188 and 190. Preferably, the boom arms 176, 178 and 180, cross members 184 and 186 and the end members 188 and 190 are all fabricated from steel and welded together to provide a rigid boom assembly 174 which is as wide as a normal grave.

A shaft 192 is mounted at the distal end of the boom assembly 174, the shaft 192 being parallel with the axle 158. Mounted for rotation on the shaft 192 are three spaced apart sprockets 194, 196, 198. Mounted on the axle 158 for rotation therewith are three spaced apart sprockets 200, 202, 204. A chain 206, 208, 210 is trained about each pair of sprockets 194 and 200, 196 and 202, 198 and 204 as shown clearly in FIG. 6. Bearing members 212 are mounted on the boom assembly 174 to provide bearing surfaces for the chains 206, 208, 210. These bearing numbers 212 may be wooden boards secured by screws or other similar means to the boom assembly 174. A plurality of teeth 214', 214", 214" is mounted on each chain 206, 208, 210. My preferred structure for these teeth will be discussed further along in this description. 7

I have provided a fluid motor 213 for pivoting the boom assembly 174 about the axle 158. In the illustrative embodiment, this fluid motor 213 comprises a hydraulic cylinder 216 pivotally mounted on a member 218 as indicated at the reference numeral 220-, the member 218 being welded or otherwise securely fastened to the cross bar 86, and a piston rod 222 (FIG. pivotally connected to a brace 224 as indicated at 226. The brace 224, which spans the boom assembly 174, is rigidly attached to the boom assembly by means such as the illustrated screws 228 (FIG. 5).

As shown clearly in FIGS. 1, 5 and 6, I have provided an auger, indicated generally by the reference numeral 230, supported by brace members 232 extending rearwardly respectively from the tracks 82 and 84 of the frame 14. The axis of the auger 230, in the illustrative embodiment, is generally parallel to the axle 158. Further, the auger 230, which is driven by a fluid motor 236, is arranged to convey earth in the direction of the arrow 234 (FIG. 6) away from the apparatus 10. It will be clear, however, that, in some embodiments, it may be advisable to arrange the auger 230 so that earth can be conveyed in either direction therealong merely by reversing the fluid motor 236.

I have shown an opening 238 in the trough of the auger 230, which opening is arranged to deposit earth into another conveyor (not shown) or some other means for conveying earth away from the grave site. Further, in some instances, it will be desirable to deposit the earth into a hopper which is left at the grave ite.

Referring to FIG. 5, it will be seen that I have provided a telescoping fender or shield means 240 pivotally connected to the auger 230 as indicated at 248. The shield means 240, which extends alongside the auger 230 between the brace members 232, is effective to deflect the earth removed by the digger 16 upwardly into the auger.

The shield means 240 comprises a first panel member 242 connected to the auger 230 for pivotal movement about the axis indicated at 248 and a second panel member 244 telescopically disposed on the member 242. The lower edge portion 246 of the member 244 will engage the ground and will prevent the flow of earth under and to the right of (FIG. 5) the auger 230. The shield means 240 is pivotally movable in the direction of the arrow 247 from its illustrated vertical position to a position in which it is held when the apparatus 10 is moved between grave sites.

I will provide side shields 249 (FIG. 5) with hook portions 249' for preventing movement of earth laterally under the tracks 60 and 62. The operator of the apparatus 10 can install and remove these shields 249 as needed to cause the earth to move toward the shield means 240.

The shield means 240 and the side shields 249 provide walls which contain the earth drawn up from a grave by the digger 16. That is, the shield means 240 and side shields 249 cause the earth brought out of the grave by the digger 16 to pile up between the digger and the auger 230 to form an earth ramp which direct or guides the loose earth upwardly into the auger. The digger 16 drags the earth out of the grave and upwardly into the space bounded by the shield means 240 and shields 249. Since one end of the digger 16 is higher than the auger 230 and since the digger is progressively pivotally moved toward the shield means 240 as will be seen in FIGS. 11, 12 and 13, the earth is moved by the digger into the auger. The concept of using an earth ramp to direct loose earth upwardly into a lateral conveyor is disclosed in US. Pat. 2,708,798 issued May 24, 1955.

Referring now to FIG. 14, a hydraulic control system for my apparatus 10 will be discussed. The control system comprises a plurality of valves 250, 251, 252, 253, 254, 255, 256 257 and the valves 122 discussed previously connected to the hydraulic pump 170. Specifically, the output side of the pump is connected to the input side of each of the valves 250-257 and 122 by lines 260 and the return side of each of these valves is connected to a storage tank 170 by a line 262. The storage tank 170' is connected to the input side of the pump 170 by a line 264.

The valve 250 is arranged to control the fluid motors 70, 72; the valve 251 is arranged to control the fluid motor 46; the valve 252 is arranged to control the fiuid motor 44; the valve 253 is arranged to control the fluid motors 150, 152; the valve 254 is arranged to control the fluid motor 213; the valve 255 is arranged to control the fluid motor 42; the valve 256 is arranged to control the fluid motor 48; the valve 257 is arranged to control the fluid motor 236; and the valves 122 are arranged to control the fluid motors 100.

In the illustrative embodiment, the valves 250-257 are all carried on a member 266 which is swingably mounted on the track 84 as indicated by the reference numeral 268 in FIG. 5. Thus, an operator of my apparatus 10 can position the valves 250-257 about the axis of the connection 268 conveniently to locate the valves for use during the operation of the apparatus 10.

Referring now to FIGS. 11, 12 and 13, the manner in which my apparatus 10 can be used to dig a grave will be discussed.

First, the frame 12 is positioned over a grave site and levelled as discussed previously. Then, the vertical frame 14, digger 16 and support 18 are moved to their illustrated, solid-line positions of FIG. 11. From these positions, the digger 16 is moved to its illustrated broken-line position 16a to define the first end wall 276 of the grave. It will be apparent that, in order to achieve the position 16a while maintaining the wall 276 vertical, the frame 14, digger 16 and support 18 all must be moved simultaneously. Specifically, the digger 16 must be tilted in the direction of the arrow 270 toward its position 16a while the frame 14 is being moved in the direction of the arrow 272 to its broken-line position 14a and the support 18 is being lowered in the direction of the arrow 274 to its broken-line position 18a.

The digger 16 is then moved from its position 16a in the direction of the arrow 278, i.e., the frame 14 is reciprocated on the frame 12 from its position 14a to its solid-line position illustrated in FIG. 12, to define the bottom 280 of the grave. From its solid-line position in FIG. 12, the digger 16 is tilted in the direction of the arrow 282 while the support 18 is lifted vertically in the direction of the arrow 284 until the solid-line position of the digger 16 shown in FIG. 13 is achieved. The illustrated solid-line position of the digger 16 in FIG. 13 defines the opposite end wall 286 of the grave. Since the digger 16 is as wide as a normal grave, its movements as illustrated in FIGS. 11, 12 and 13 will completely excavate a grave. From its solid-line position in FIG. 13, the digger 16 is tilted in the direction of the arrow 288 to its position 1612 above the grave.

All of the movements illustrated in FIGS. 11, 12 and 13 are accomplished by manipulation of the valves 250, 253 and 254. That is, the valve 250 is operated to reciprocate the frame 14 on the frame 12, the valve 253 is operated to reciprocate the support 18 on the frame 14 and the valve 254 is operated to tilt the digger 16 on the support 18.

Referring now to FIGS. 7 and 8, the preferred structure for the teeth 214, 214", 214" will be discussed. The tooth 214 (FIG. 7) is proportioned and designed to cut a fiat side wall for a grave and the tooth 214 (FIG. 8), which is my basic tooth structure, is proportioned and 7 designed to operate effectively in all types of soil in all types of weather conditions.

The tooth, 214" is fabricated by forming a steel strap 290 to have a main body portion 292, a curved portion 294 at each end of the main body portion 292 and an extension portion 296 extending from each curved portion 294 parallel to the main body portion 292. Brackets 298 are connected to the mid-point of the main body portion 292 by fastening means indicated at 300. The brackets 298 are utilized to connect the tooth 214" to one of the chains 206, 208, 210, a run of the chain 208 being indicated by a dashed-line in FIG. 8. Preferably, the main body portion 292 will extend perpendicularly to the run of the chain and parallel to the axle 158. Each of the curved portion 294 is formed about an axis which defines an acute angle with the chain 208 at a point to the rear of the tooth 214", i.e., to a point on the chain which follows the tooth as it moves about its path. Thus, the extension portions 296 extend forwardly of the main body. portion 292 to provide leading edges for the tooth L The curved portion 294 and extension portion 296 at each end of the main body portion 292 provides a pocket or space for receiving the earth and for dragging the earth upwardly from the excavation.

The illustrated teeth 214" (FIG. 6) are similar to the teeth 214 except that the main body portions and extension portions of the teeth 214" are shorter than the main body portions 292 and extension portions 296, respectively, of the teeth 214". As seen in FIG. 6, a tooth 214" is located on the chain 208 just behind each tooth 214" and a tooth 214" is located behind each tooth 214 on the chains 206 and 210.

Each tooth 214 comprises a metal strap 304 formed to have a main body portion 292', a curved portion 294' and an extension portion 296 at one end of the main body portion 292' and another extension portion 312 at the opposite end of the main body portion 292. The curved portion 294' and extension portion 296' (FIG. 7) correspond respectively to the curved portions 294 and extension portions 296 of the tooth 214". The extension portion 312 which is bent at a right angle to the main body portion 306 is effective to cut a fiat side wall for a grave.

Referring now to FIGS. 9 and 10, an illustrative means for cleaning the teeth 214 will be discussed. In FIGS. 9 and 10, it will be seen that I have illustrated a member 314 secured to a member 315 extending under the boom assembly 174 by means of a screw 316, the member 314 having a portion extending upwardly toward the chain 206. A steel spring 318 is welded or otherwise securely fastened to the upper end of the member 314 so that it will extend generally parallel to the main body portions of the teeth 214 carried on the chain 206. The ends of the spring 318 extend into the pockets or spaces formed by the curved portions 294 of the teeth 214 to remove earth from such pockets or spaces. Specifically, when the illustrated tooth 214" moves in the direction of the arrow 320 (FIG. 10), each end of the member 318 will wipe away the earth being carried by the tooth 214'. Such a cleaning means will be associated with each chain 206, 208, 210.

The illustrated member 315 may be positioned to extend transversely across the boom 174 at a convenient point between the boom member 190 (FIGS. 6 and 9) and the pivot axis of the boom.

What is claimed is:

1. An excavating apparatus comprising a boom-type digger, first means for supporting said digger for pivotal movement about a generally horizontal axis at one of its ends, second means for supporting said first support means for generally vertical reciprocation, third means for supporting said second support means for generally horizontal reciprocation in a direction generally perpendicular to said horizontal axis, whereby the pivot axis of said digger can be reciprocated both vertically and horizontally, means for conveying earth away from said apparatus and depending shield means cooperating with said digger to direct and guide earth excavated by said digger upwardly into said conveying means, said shield means comprising a first panel member pivotally connected to said conveying means and a second panel member disposed for telescopic movement relative to said first member, the lower edge portion of said second panel member being arranged to engage the ground.

2. An apparatus as in claim 1 wherein said conveying means is an auger extending generally parallel to said pivot axis, said auger being carried by said second support means for movement therewith, and wherein said shield means is supported for pivotal movement about an axis parallel to said first-mentioned axis.

3. -An excavating apparatus comprising a boom-type digger, first means for supporting said digger for pivotal movement about a generally horizontal axis at one of its ends, second means for supporting said first support means for generally vertical reciprocation, third means for supporting said second support means for generally horizontal reciprocation in a direction generally perpendicular to said horizontal axis, whereby the pivot axis of said digger can be reciprocated both vertically and horizontally, means for stationarily supporting said third means above an excavation site, said third support means comprising frame means including a pair of parallel tracks, and further comprising a pair of drive wheels, means for independently driving each Wheel, and means for mounting said wheels on said frame means whereby said frame means can be transported to an excavation site and positioned at the site, said mounting means comprising bracket means mounted for reciprocation on each of said tracks, and means for removably mounting said Wheels respectively on said bracket means.

4. An apparatus as in claim 3 wherein said second support means is carried by said bracket means.

5. An excavating apparatus comprising a boom-type digger, first means for supporting said digger for pivotal movement about a generally horizontal axis at one of its ends, second means for supporting said first support means for generally vertical reciprocation, third means for supporting said second support means for generally horizontal reciprocation in a direction generally perpendicular to said horizontal axis, whereby the pivot axis of said digger can be reciprocated both vertically and horizontally, means for stationarily supporting said third means above an excavation site, said third support means comprising frame means including a pair of parallel tracks, and further comprising a pair of drive wheels, means for independently driving each wheel, and means for mounting said wheels on said frame means whereby said frame means can be transported to an excavation site and positioned at the site, said mounting means comprising first bracket means mounted for reciprocation on each of said tracks, and second bracket means mounted on each of said wheels, each second bracket means being proportioned and designed to be releasably connected to one of said first bracket means.

6. An apparatus as in claim 5 wherein said bracket means are arranged so that each wheel can be selectively mounted on either side of its associated track.

7. An excavator comprising first frame means including a pair of spaced apart, parallel first tracks, means for stationarily supporting said first frame means above an excavation site with said first tracks being disposed above and on opposite sides of such a site, second frame means mounted for reciprocation on said first tracks, said second frame means including a pair of spaced apart, parallel second tracks, said second tracks being generally perpendicular to said first tracks, support means mounted for reciprocation on said second tracks, a boom-type digger, means for mounting one end of said digger on said support means for pivotal movement about an axis generally perpendicular to said first and second tracks, the other end of said digger being movable through the space between said first tracks to engage the ground, said digger comprising rotor means at each of its ends, at least one endless chain trained about said rotor means, and teeth carried by said chain, driving means carried by said support means, means for drivingly connecting said chain to said driving means, first fluid motor means for reciprocating said second frame means on said first tracks, second fluid motor means for reciprocating said support means on said second tracks, and third fluid motor means for pivoting said digger about its axis, a fluid pump connected to said fluid motor means, means for drivingly connecting said fluid pump to said driving means, a plurality of leveling arms pivotally mounted on said first frame means and arranged to engage the ground to support said frame means, fourth fluid motor means for adjustably positioning each of said arms, said fourth fluid motor means being connected to said pump, a pair of wheels, bracket means mounted for reciprocation on each of said first tracks, means for removably fastening said wheels to said bracket means, and fifth fluid motor means for independently driving each of said wheels, said fifth fluid motor means being connected to said pump.

8. An excavator as in claim 7 wherein said bracket means are connected to said second frame means for reciprocation therewith.

9. An excavator as in claim 8 further comprising auger means for conveying earth away from said excavator, and sixth fluid motor means for driving said auger means, said sixth fluid motor means being connected to said pump.

10. An excavator as in claim 9 wherein each of certain of said teeth comprises an elongated member formed to have a main body portion extending generally perpendicular to said chain and parallel to said first-mentioned axis, said chain being connected to said main body portion at a point intermediate its ends, a curved portion at each end of said main body portion and a generally flat extension portion connected to each of said curved portions and extending generally parallel to said main body portion and inwardly toward said chain, said curved portions curving outwardly from said digger, each of said curved portions being formed about an axis which forms an acute angle with said chain at a point on said chain following said tooth whereby said extension portions project forwardly of said main body portion in the direction of movement of said chain.

References Cited UNITED STATES PATENTS 883,017 3/1908 Heck 37-97 1,052,972 2/1913 Sargent 198-144 1,224,323 5/1917 Rice 37-90 1,745,090 1/1930 Geithie 37-191 1,796,184 3/1931 Barber 37-86 2,231,983 2/1941 Zuckerman 37-86 2,692,446 10/1954 Smith 37-86 2,708,798 5/1955 Warner et al 37-86 2,782,534 2/1957 Wall 37-85 2,804,174 8/1957 Chasar 280-34X 2,857,725 10/1958 Canfield 56-254 2,991,571 7/1961 Hyster 37-191 3,015,175 1/1962 Smith 37-192 3,033,523 5/1962 Mulholland et al. 280-150.5X 3,035,821 5/1962 Peterson 37-192X 3,050,881 8/1962 Brown 37-191X 3,175,570 3/1965 Voreaux et a1. ISO-66X 3,398,471 8/1968 Brown 37-86 FOREIGN PATENTS 131,455 2/ 1949 Australia 37-89 5 ROBERT E. PULFREY, Primary Examiner C. D. CROWDER, Assistant Examiner US. Cl. X.R. 

